Kinetic Energy
by CancerTheCrab
Summary: When a new metahuman charges Barry full of kinetic energy, Team Flash has no option but to lock him in the particle accelerator and wait for it to wear off. The problem is that because of his accelerated healing, he's left in a perpetual state of agony and high fever. Rated (high) T for language and dark themes. Trigger warning inside. One-shot.


**A/N:** Alright so it took me quite a while to finish this and I'm actually pretty proud of it, because it's so long. I won't be making a sequel or anything like that, by the way. Oh and I don't really ship Westallen that much but if you do then go ahead and squint because this is set sometime after Season 2 Episode 6: "Enter Zoom" (so spoilers). I hope it isn't too OOC, but personally I think I did a good job.

 **Trigger Warning (TW):** (Temp.) Suicidal thoughts and actions

 **Kinetic Energy**

oO-Oo

Today was a day like any other for Barry Allen. He woke up and saw that he was late for meeting his friends at S.T.A.R. Labs. He was _always_ tardy to pretty much everything he could be late to. It was pretty amazing, but certainly not as amazing as the fact that he is the Flash. The very same Flash that saved Central City many a time from metahumans and black holes. Actually, that makes it all the more hilarious that he was always late. With his super speed, he should be on time, or better yet early, to everything. Despite that, he's late to meetings, training, crime scenes with Joe, and everything else he did.

Everything except protecting his city and its people, of course. Like last night, when he fought a metahuman that used various aromas to manipulate her opponent. For example, she stuffed Barry full of a muscle relaxant and pain inducer. (His nerves were still very sensitive, anything that touched his skin felt like sandpaper and the needle that Caitlin used to hook him up to an IV was pure hell. He was too nauseated to actually eat last night, so it was inevitable.) So this morning he got up nice and slow until he caught a glance of his clock which said 9:01 AM. From that point on, his use of powers consisted of fighting cavities and saving time. It was 9:05 when he sped over to the Cortex where Caitlin and Cisco were going to help him improve his speed and find possible new abilities. The power of speed is broad and mighty, so they didn't doubt the ability to do so.

"Hey, guys, sorry for being late-"Barry was interrupted by Joe.

"How is it that despite being the _Flash_ you're always late?" He exclaimed. Barry smiled sheepishly and walked over to Caitlin and Cisco, who were standing by the monitors outside the treadmill room.

"Alright, Barry, today we're going to work on endurance. Run as fast as you can for as long as you can." Caitlin said.

Barry stepped onto the treadmill and stretched out his hamstrings and arms, cracking his neck. He began to jog, then sprint and built up speed. Just as Barry became a streak of blue, grey, and yellow lightning, Joe's phone chimed. "Wait! We've got a crime scene, I just got a message. Come on, Barr."

oO-Oo

The crime scene was at a factory where apparently a worker had been attacked. "Wow." It was the only word that came to mind as he looked at the victim. Well, what was left of him. "Wow," he said again.

"Yeah. What could've done this, Barry?" Joe asked. Barry was kneeling by a spot of black, or more accurately soot, and the only distinguishing feature was clean spot in the shape of two shoes.

"Well the non-metahuman cause would have to be spontaneous combustion, but since the witnesses said that there was someone else here, it's definitely not that. Even if there wasn't anyone spotted, I never bank on spontaneous combustion. It also seems like the victim wasn't lit on fire, there are no signs of struggle. You should probably alert the police that this isn't something they can fight. I'll tell everyone else."

"Alright. But, Barry, for the love of God, don't go running off and fighting whoever this is on your own."

"Joe, when do I ever do that?" The cop stared at Barry with a judgmental look. Of course, he knows that the man is holding himself back from slapping him upside the head.

"I don't even know how to answer that. Just don't do anything stupid."

"Can't promise anything, Joe."

oO-Oo

Team Flash was gathered in the Cortex, peacefully working on their respective projects. Barry and Caitlin were studying the former's speed and trying to improve it, and Cisco was fiddling with the suit. On the treadmill, Barry was trying to pass Mach 2, but he couldn't even reach it.

"Gah!" Barry nearly fell off the treadmill. He was unable to go that fast. The frustration showed crystal clear on his face and his body language. "Why can't I go faster?" He rubbed his face with one hand and steadied himself on his knee with the other.

"I don't know Barry, but you'll get it. I know you will." Caitlin reassured. She walked into the room and helped him to hers to examine him. She took a blood sample, checked his pulse, and general just poked and prodded him. Suddenly, a monitor gave a loud ping in the middle room.

Cisco turned to the two and said, "There's something going down right outside the Central City police station!" Barry super-sped, putting on his suit in a blink of an eye, and the only trace that he left was the papers disrupted. Cisco and Caitlin ran over to the computers to keep an eye on him through the suit. Meanwhile, the Flash had already arrived at the precinct to see that a shady-looking man was holding his open palm out at an officer.

"Guys! There's no gun, he doesn't have a weapon. I think it might be-"He was interrupted by a bloodcurdling scream that came from the cop targeted by the man. His skin glowed bright yellow and appeared to crack. Barry's eyes widened underneath his mask as the man closed his hand, and instantly the officer burst into flames. Seconds later, his body crumbled into nothing but dust. "-A metahuman. Oh God." He ignored Cisco and Caitlin's questions and looked at the remaining terrified policemen and yelled, "Run!" They did. They turned on their heels and ran in the opposite direction that the metahuman was and into the building. Barry saw something out of the corner of his eye. The spot where the officer was had ash and the outline of shoes. Just like the crime scene.

" _Barry!_ _What the hell was that?_ " Cisco yelled into the microphone.

"He- I don't- the metahuman just _pointed_ at a guy and he…I don't know he caught on fire? No- he burst into flames. He didn't even have to _touch_ him." Barry felt like throwing up. Fear and panic swirled around his brain, which was screaming at him to choose fight orflight.

Of course Barry had to fight.

Caitlin said desperately, " _Barry, don't engage him, we don't know what he can do!_ " It was too late, though, he'd already caught the attention of the metahuman. _Combustion,_ his subconscious whispered. It was a lame name, something that Cisco would probably scoff at. Oh well.

The man looked at Barry with contempt and snarled, "I don' think you wanna fight me, Flash. Just 'cause you're fast don' mean you're strong." He had a thick New Yorker accent.* The world slowed around Flash just as the man raised his hand. Something flew at him, a streak of energy he hadn't been able to see before.

"Jeez!" The asphalt darkened where his heels dug into the ground. He'd run behind Combustion to avoid whatever the hell it was that he'd thrown. "Rude. No warning?" Barry knew it was dangerous to tease his enemies, but he couldn't help it. The villain let out a yell of frustration and thrust out both palms this time. Flash ran around him, dodging as best as possible while asking his team, "He's…um, he doesn't do much other than throw some yellow light thing at me but I don't think punching him will do me much good."

" _Good idea. Whatever he can do might be activated by touch as well, so don't touch bare skin. Maybe grab him by his clothes_ ," Caitlin replied.

…

Joe had decided to walk in at that moment and say, "Cisco, Caitlin, what's going on? I got a distress signal from the precinct, and then a message not to approach." Cisco let out a _very_ masculine scream and Caitlin yelped _very_ professionally. The detective had been silent when approaching the lab until he spoke, so they'd been taken by surprise. Joe's eyebrows rose, but he gracefully ignored how hilarious the scientists looked and continued, "Is Barry over there?"

"Yeah- uh- there's a metahuman he's fighting. I'm worried, though, about the ability. Barry said that someone _exploded_?"

"And you let him fight the guy alone?" Joe said, his question more of a statement, eyes darkening.

"Should-should we have called Arrow or something?" Cisco spluttered.

Joe threw his hands in the air, "Yes!"

…

Meanwhile, Barry was panicking. This guy was clever, not some meathead thug that he deals with on a daily basis. Despite his build and appearance, he was witty and smart. His moves were tactful and precise; he used both hands and anticipated where Barry would run next. The speedster heard his team arguing over the comm., and in any other situation he would've laughed at the sound of his father telling Cisco and Caitlin off. However, he was too busy trying to save himself from turning into ash. Combustion jabbed both palms _behind_ Flash this time, forcing him to twist around quickly to see that some of the police officers were gathered stupidly at the doors of the precinct. The streak of light was making its way to a young policewoman, blond and short, which he recognized as Michelle Roster. She was sweet and most definitely did _not_ deserve to be burnt alive.

Barry ran. He barely touched the ground with his feet, arms pumping at his side. He felt the Speed Force pushing him toward the cop. He felt the lightning race through his veins. Cisco's voice slowed almost comically in his ears alongside his too-quick heartbeat thundering in his body.

 _Thump-thump-thump_

Barry calculated the distance between him, Michelle, and the light, and the rough estimate of his speed. There were 3 ways to save her. One: grab her and keep running. The worst that would do is knock the breath out of her and also get her killed because the angle at which he'd get her would still get her hit by the light. Two: push her back. This would get her injured, and probably killed, seeing as pushing her would knock her into a wall at over 900 mph.

 _Thump-thump-thump_

He hated option number three. Oh, well. Better Barry than innocent Michelle, right? _Right_?

 _Thump-thump-thump_

Barry twisted on his heel as he skidded in front of Michelle, baring his chest to the streak of light. It hit him hard and then sank into his body. Immediately, his skin glowed golden, his eyes a similar color. His entire being felt like he was on fire, every single molecule bursting into flames, his nerves (which were still raw from yesterday) going off. All five senses dulled down and the world around him fell away. In his little vacuum of space all that existed was pain. Distantly, he heard a tortured scream, and he realized it was him.

The world stopped imploding, the pain didn't stop, and he could now hear Joe and Cisco yelling at him.

" _Barry! Barry! Come on, what happened, what's wrong?_ " Joe asked. Caitlin was staring, baffled, at the screen in front of her. It showed Barry's vitals spiking but she couldn't identify what was wrong.

" _Barry, talk to me_ ," she pleaded. He was unable to answer as he fell to his knees and Combustion ran away, laughing. Barry muffled another scream against his glove, biting down on the leather. His eyes prickled but no tears fell. He ignored the calls of the officers and super-sped back to STAR Labs out of habit. His legs stuttered to a stop as he ran into the Cortex and the short moment lucidity slipped past his twitching fingers. Everything before him blurred until all he could see was vague shapes. He realized that his entire body was vibrating quickly and the floor under him began to smoke. "Barry, you need to stop!"

Barry thought that maybe he was shaking his head. He was beginning to see a bit clearer, so in his mind he pieced together that if he super-sped, the pain would stop. In this state, his primal need to stop _hurting_ took over any other thought. So he got up and made his legs move, ignoring that he crashed into the wall. Turning, he ran again and in the blink of an eye he'd barreled into the other wall. Over and over again, he ran into things until he finally made it out of the Cortex and could run longer distances without crashing into anything.

In the Cortex, however, Caitlin was yelling at Cisco, "Get the tranquilizer! Barry's fever is fatal for a regular human; we _have_ to get it down!"

"So we _shoot_ Barry?"

"We have no other choice, I have to see what the hell that metahuman did to Barry!"

"Okay, fine! Fine!" Cisco ran to grab the gun and put a dart in, and then grabbed 3 others. After the fiasco with Zoom, Harry, Caitlin, and he had upped the dosage and overall affect. He wasn't sure what it would do to Barry but after seeing him run much, much faster than he ever had, it was obviously necessary. He ran down the hallway after shoving a comm. in his ear.

Caitlin's voice crackled through, " _Please hurry, Cisco. He's getting worse._ " Cisco was just about to tell her that he has no idea where the speedster is when a streak of yellow slammed into him. _Holy shit_ , Cisco thought to himself. Seeing as he hadn't run away yet, Barry must be pretty dazed. Cisco took the advantage and rolled over onto his friend and took a dart out of his back pocket. Instead of shooting him at point blank and no doubt giving him one hell of a bruise, he simply pricked Barry on the arm. His friend was unresponsive, though. He didn't do anything but stop vibrating.

"I think I found him," Cisco said.

" _Alright, once you have him sedated bring him to the particle accelerator. I don't know what's wrong with him but I think it'd be best to have him in one spot._ " Caitlin said.

"We have to lock up Barry? Like a metahuman?" Cisco didn't like the sound of that. Barry was his friend, a close one at that. He didn't want to shut him in a cell.

" _It's the only way to be able to check him out. I know you don't want to do it, neither do I, but we have to._ "

"Fine. Tell Joe to come help me."

oO-Oo

When Barry regained consciousness, he had a couple seconds of clear thoughts. His eyes focused and he could see his friends but they were on the other side of glass. He blinked and looked up and after a moment realized that he was in the particle accelerator. This time, though, he was locked in one of the cells.

By the time he'd deducted that much, his senses had come back. This meant he could feel again. Immediately Barry started to vibrate his body against his will. It felt like someone had bottled pure energy and rigged up a high power hose in his body. It overflowed and pushed against his skin, his bones, his muscles, and it _burned._ His lungs pushed a scream out of him that tore at his throat and made his head pound, but he couldn't stop. Barry pushed himself on his feet and didn't hear Caitlin telling him to sit down. His staggered a bit but forced himself to run. As soon as he did, he collided with a wall. So he turned around and ran the other way. He tried over and over again to run, to get rid of the energy burning his lungs, his stomach, and his entire body.

Caitlin turned away, biting her lip to keep from crying. Barry was in pain and confused, but there was nothing they could do for him. She had only 5 minutes to check his vitals when he was passed out and after speculating and even asking for help, she had realized that the metahuman had the ability to increase kinetic energy. They guessed that he had realized that if he increased it enough, any object or person would burst into flames. However Barry's accelerated healing kept his cells from disintegrating, but that was it. He had a high fever and the effects would only wear off with time. The only thing they could do is sit, wait, and hope he doesn't hit the wall too hard. It was torture for Caitlin, who is a doctor that _needed_ to heal, to help. Of course it was nothing compared to what Barry must be feeling.

Cisco had needed to excuse himself. Joe had insisted on staying here with Caitlin to watch over his son, so the two of them sat down on the cold metal together and tried not to lunge over to the controls and let him go. This was for the best, after all.It just didn't feel like the right thing.

It took about 3 hours for Barry to stop slamming into the walls in an attempt to burn off the energy, but at one point he had finally collapsed to the ground. He still vibrated, somehow, even though the particle accelerator was meant to stop any and all metahumans from using their powers. That was all he did, though. He just laid there and vibrated, presumably too tired to run. (They didn't want to think about the possibility that he was too injured.) That is, until he rose to his hands and knees and crawled forward toward the glass. Caitlin moved forward and strained her ears for Barry's weak words.

"Please…please let me go…it hurts." He whimpered and collapsed against the glass, pawing at it.

"I'm so sorry Barry, we can't. Not yet." Caitlin had to hold back a sob. In the Cortex, Cisco was pacing around the room and punched a wall when he heard his friend's pleads. Caitlin reached out and placed her hand against the glass where Barry's was. It was heating to a pleasant temperature, as was any other glass he touched. She watched as a few tears rolled down his cheeks only to turn into steam before they reached his chin. He let out a small sob and went back to vibrating violently.

Joe clenched his hand and stalked out of the room, heading toward the Cortex where was still sitting. He approached the scientist and asked, " isn't there _anything_ you can do? He's in pain!"

"I know he's in pain, Joe, but he'll burn through any medicine we can give him. There's nothing in this world that can suck the kinetic energy out of an object, much less a person. Even if there was, we can't be sure of the outcome or if it has the potential to harm or _kill_ Barry." The older man said. It was obvious he had been mulling over any option they had. The result was always the same: they just need to leave Barry to burn off the energy on his own. If they let him run loose, no one knows where he would end up or if he would hurt himself. As an added worry, he might run half way across the world and get stranded on some foreign continent because he's tired himself out so much that he can't run. They just couldn't risk it.

Joe slumped into a chair and tried not to think about his son's suffering. He'd been sitting for about 15 minutes when Iris walked into the Cortex, 4 coffees in a carton and one in her hand and a smile on her face. Her expression morphed into one of worry when she saw that not only Barry wasn't there, but Caitlin wasn't either. Cisco, Joe, and all looked disgruntled and worried, too. Plus, the scientist was usually with his wife and only came when the team needed a consultant.

"Hey, guys…what's wrong? Did something happen to Barry?" She set down the coffees at the desks with the monitors.

"Hey, baby," Joe said, hugging his daughter, "Yeah. Yeah Barry got hurt." He tightened his hold on her when he thought about his other child, injured down in that cold cell.

Iris pushed him away gently and asked, "Well, where is he? And Caitlin?"

"They're both down at the particle accelerator," Cisco said. It was disconcerting for him to be so serious. Something must be very wrong.

"Okay, what are you guys telling me? Why isn't Caitlin patching up Barry over here?"

Cisco answered again, "You better sit down, it's a long story."

Her heart sank lower and lower as Cisco and explained what had happened to Barry. As soon as the two were done talking, she sprung to her feet and ran down to the particle accelerator. Joe and Cisco followed her but excused himself to go home to his wife now that he wasn't needed. He told the detective to update him when Barry was feeling better.

Her face crumpled when she saw him, "Oh, Barry." She walked forward and kneeled next to Caitlin, who greeted her quietly.

Barry scrambled to get up. _Iris,_ he thought _, Iris is good. She doesn't want to hurt me, to keep me here._ "Iris…" He sobbed. "Let me go, please, p-please, tell them to let me go. H-hurts." Iris placed one hand on the glass and one on her mouth, tears gathering at the corners of her eyes. She wished with all of her being that she could be there for him, to hug him and tell him it would be over soon. But, according to Cisco it would take _hours_ for him to burn it off.

"Barr I'm sorry I can't let you go. Just hang in there, Barr, it'll be okay." She hated the way any hope in his eyes burned out at her words and how he slid down the glass, curling up on himself. She hated how his shoulders shook with pain and sobs.

oO-Oo

It took exactly 10 hours, 34 minutes, and 6 seconds for Barry to burn off all the excess energy. Throughout all 10 and a half excruciating hours he had begged and pleaded to be let out. Half way through, however, he started beg to be killed. It has been _hell_ hearing him tell them that he'd rather be dead than be in this much pain. He'd scratched at his arms and drew blood but had realized quickly it wouldn't do much and instead opted to get up and try to run himself into the walls. At one point he really had hit the wall too hard and knocked himself out, which was good _and_ bad. On one hand, he could have a concussion, but on the other hand he couldn't hurt himself anymore or beg them to kill him.

Caitlin confirmed that his vitals showed his fever was down so it was safe to get him out and treat him. Joe stepped into the cell once Cisco opened the doors and scooped up his son in bridal style. He was so light, so limp and pale, that the older man could've thought him dead if it weren't for the rise and fall of his chest. Iris and Cisco trailed behind him while Caitlin strode back into the Cortex, having already laid out all of her equipment hours ago.

"Why aren't his arms healing, Caitlin?" Iris asked. The scratches on the soft flesh of the inside of his arms were indeed still there, though they had stopped bleeding already.

"I believe that his accelerated healing was focusing on his cells and keeping him from bursting into flames, so until now no other wounds were healing." She explained, looking pained. "Joe, could you set him down over here?" She gestured to a bed and thanked the man when he complied. Now all she needed to do is disinfect his scratches and make sure his head okay. "I'm going to take some scans. He's going to be okay." The words sounded hollow after seeing him suffer for so long. She deducted that he had a mild concussion, bandaged his arms, and then checked him over to see if the fight with the metahuman earlier had injured him, too. When she saw that he was fine other than being exhausted, hungry, and thirsty she pulled up a chair by his head and reported to Iris, Joe, and Cisco. "He just needs to rest, now."

Joe asked, "What about the metahuman that did this?"

"I was thinking about setting a trap for him, actually. Y'know, a big ol' hole with a bunch of man-eating animals in it. Something that likes to play with its food." Cisco said darkly. He was _angry_. He was furious, actually, rage bubbling up in his stomach and racing through his veins. Everyone felt the same, wanting to take revenge and make that man suffer like he had done to Barry.

"I think that the trap is a good idea, but Barry wouldn't want us to kill anyone." Caitlin said, sounding disappointed. As a doctor, her purpose was to heal and do no harm. Now, though she was Caitlin Snow, friend of Barry. (And she knew exactly where to stab or shoot someone to make them scream.) They all thought quietly for a moment until a low moan interrupted them. Barry's eyes fluttered open and his eyes wandered, unfocused. Then he saw his friend's worried expressions.

"Hey guys," he whispered, and then winced when he head gave a spectacular throb.

"Hey Barr, how're you feeling?" Iris asked quietly, being mindful of his headache.

"Tired and sore. My head hurts. My arms are sort of itchy, too." He answered. "Thanks for not letting me out," he said, making them flinch. "Sorry."

"No, no Barry, we're sorry you had to go through that." Caitlin said, Cisco nodding fervently.

"'S not your fault," he slurred, already half asleep again. Iris laced their fingers together and Joe put a warm hand on his shin. Before he could go to sleep, though, Caitlin asked him some simple questions. 'What year is it', 'What is Joe's last name', things like that. He answered all of the questions correctly and was allowed to fall asleep. She would have to wake him up every few hours to make sure he's okay, because of his concussion.

They sat around his bed as he drifted off into a peaceful, deep sleep, each of them wanting (needing) to see him calm and no longer in pain. Barry looked so much younger when he was asleep, so innocent and undamaged. The cruel reality was that he scarred and hurt emotionally, mentally, and physically. That doesn't matter, though. His team would always, _always_ be there for him.

oO-Oo

In the end, Combustion AKA Richard Rogers, had 5 broken bones, 7 fractures, and a parade of bruises.

oO-Oo

 **A/N:** *I don't know what the heck a New Yorker accent sounds like I am so sorry if I butchered it or offended anyone


End file.
